# RHSA-2021:3155: thunderbird security update

RHSA-2021:3155, released August 16, 2021, fixes 6 CVEs in thunderbird (version 0:78.13.0-1.el8_4). None of them is reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/fix/linux/rhsa-2021-3155
- Platform: Linux
- Released: Aug 16, 2021
- Priority: High (Closes CVE-2021-29985, high severity)
- CVEs: 6, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://access.redhat.com/errata/RHSA-2021:3155

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [thunderbird](https://patchblox.com/security/data/product/linux/thunderbird.md) | RHEL 8 | 0:78.13.0-1.el8_4 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-29985](https://patchblox.com/security/data/cve/CVE-2021-29985.md) | High | Firefox ESR and 3 others: A use-after-free vulnerability in media channels could have led to memory corruption and a potentially… | 8.8 | 0.0145 |  |
| [CVE-2021-29980](https://patchblox.com/security/data/cve/CVE-2021-29980.md) | High | Firefox ESR and 3 others: Uninitialized memory in a canvas object could have caused an incorrect free() leading to memory corruption… | 8.8 | 0.0140 |  |
| [CVE-2021-29984](https://patchblox.com/security/data/cve/CVE-2021-29984.md) | High | Firefox ESR and 3 others: Instruction reordering resulted in a sequence of instructions that would cause an object to be incorrectly… | 8.8 | 0.0139 |  |
| [CVE-2021-29988](https://patchblox.com/security/data/cve/CVE-2021-29988.md) | High | Firefox ESR and 3 others: Firefox incorrectly treated an inline list-item element as a block element, resulting in an out of bounds… | 8.8 | 0.0138 |  |
| [CVE-2021-29989](https://patchblox.com/security/data/cve/CVE-2021-29989.md) | High | Firefox ESR and 3 others: Mozilla developers reported memory safety bugs present in Firefox 90 and Firefox ESR 78.12. | 8.8 | 0.0127 |  |
| [CVE-2021-29986](https://patchblox.com/security/data/cve/CVE-2021-29986.md) | High | firefox: Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability.  This... | 8.1 | 0.0126 |  |

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Data as of 2026-11-07T12:40:37Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo